Method of inhibiting gum formation in cracked hydrocarbons



Patented Sept. 5, 1939 PATENT OFFICE METHOD OF INHIBITING GUM FORMATION IN. CRACKED HYDROCABBONS George W. Ayers, In, Chicago, Ill., assignor, by

memo

assignments, to Gasoline Antioxidant Company, Chicago, 111., a corporation of Delaware No Drawing. Original application April 28, 1932,

Serial No. 608148.

Divided and this application. May 13,1937, Serial No. 142,491

3 Claims.

This application is a division of application Serial No..608,l48, filed April 28, 1932, which application is a continuation-in-part of Serial Number 309,685, filed October 1, 1928, in which application I have disclosed the treatment of cracked highly unsaturated hydrocarbon motor fuel distillates of less-readily detonating type, with various chemical compounds for the purpose of inhibiting development (or otherwise curing the same) of gum deposits or objectionable color, or

both.

Cracked petroleum products, particularly gasoline, upon being exposed for some time to air, light or heat, form resinous materials which may be dissolved by the petroleum product or which may form an insoluble deposit. These resinous products are formed particularly in large amounts when vapor phase gasoline, that is, gasoline which contains a large percent of unsaturated compounds, is stored for several months. If a tank of such gasoline, for example, were exposed for some time to the heat of the sun or to contact with air or both, formation of these undesirable resinous products would ordinarily take place. If these gums were permitted to form and remain in the motor fuel product, they would seriously interfere with the proper flow of the motor fuel through the fuel passages of internal combustion engines by clogging such passages against the free and proper flow of the fuel to the combustion cylinders. On the other hand, it is important to have a large amount of unsaturates present in the gasoline, since such unsaturated compounds give the motor fuel a high anti-knock value. The problem, of course, is to keep them in the fuel, without forming objectionable gums, resins, or color.

In application Ser. No. 309,685 hereinabove mentioned, I have disclosed a number of tests upon various organic compounds for the purpose of inhibiting the formation of gums and resins in cracked motor fuels, and for the purpose of stabilizing the characteristics of cracked gasoline. Among such compounds tested were hydrocarbons having more than one benzene ring as a nucleus,

comprising those hydrocarbons classifiable as aromatic hydrocarbons having a plurality of combined benzene rings; and also polyhydroxy-aromatic compounds generally. Specifically, I disclosed in the aforesaid application Ser. No. 309,- 685, examples of gum inhibiting tests upon bydrocarbons having more than one benzene nucleus such as alpha-naphthylamine, beta-naphthol, and others, and in the present application it is my desire to restrict my claims to polyhydroxy aromatic compounds broadly, and specifically to the hydroxy compounds of the poly-nuclear benzene ring. Such hydroxy compounds have been found to possess qualities which render them adaptable as negative catalysts or inhibitors, and as disclosed in my prior application, the best inhibiting efiect is obtained with the compounds having the greatest number of hydroxy groups. It will be, of course, understood that other hydroxy compounds of the polyhydroxy aromatic group may also be used, such as 1:4-dihydroxynaphthalene [C1oHe(OH) 2] 1 2-dihydroxynaphthalene; alizarin 0 Canon 0B4\ J0/ dihydroxyphenanthrene [Ci4I-Ia(0H) a] others of this classification.

I prefer to treat the cracked distillate with a polymerizing catalyst such as fullers earth prior to the addition of any of the aforesaid gum inhibiting agents or combination of the same. The fullers earth or equivalent polymerizing catalyst removes part of the gum and color forming constituents, but leaves intact those unsaturated compounds which are valuable to gasoline or other motor fuels for their anti-knock properties. The fullers earth removes selectively objectionable unsaturated compounds and retains simultaneously in the fuel valuable unsaturated compounds. Certain of these valuable unsaturatw would, of course, eventually form gum deposits. but they are prevented from so doing by the addition to the motor fuel of one or a combination of the herein described inhibiting agents.

The inhibiting agent may be added prior to treatment with the polymerizing catalyst, but it is preferably added afterward. It will also be understood that the polymerizing catalyst -(such and as fullers earth) may be dispensed with, but it is preferably used to give a better product. In any case, the inhibiting agent. should be used. only. in an amount suflicient to substantially inhibit gum formation. These amounts will vary in accordance with the nature of the cracked gasoline or distillate used, but the amount should not exceed a fraction of one per cent, in general .not more than 0.3%, and preferably about 06%. In other words, a small proportion of inhibitor should be used in accordance with the desired needs.

What I claim is:

1. A cracked gasoline normally tending to form h gummy substances upon storage and containing a polyhydroxyphenanthrene compound in sum.- 3. A cracked gasoline normally tending to form clent quantity to retard gum formation. gummy substances upon storage and containing 2. A cracked gasoline normally tending to form dihydroxyphenanthrene in suflicient quantity to gummy substances upon storage and containing a retard gum formation. 5 dihydroxyphenanthrene compound in sumcient quantity to retard gum formation. GEORGE W. AYERS, JR. 

